9 RiversWater is an important resource we all need to live and survive. 70% of our bodies are water.We see water all around us in the sea, lakes, ponds and rivers.We are now going to take you on a journey to find where our water comes from and how rivers affect our lives.

14 Top uses of waterPut list of uses for rivers in order of importance for:TodayThe past

15 Past uses of water No washing machines/ dish washers– wash by handMore travel by boat, few went by planeMore baths, less showersNo sprinklersLess swimming pools – more swims in the lakeNo automated car washesFewer golf courses – use a lot of water

23 1. Source: the point at which the river starts.2. Interlocking spurs: where the river winds between ridges.3. Gorge: deep valley caused by wearing back of a waterfall.4. Waterfall: often where the river crosses a band of harder rock.5. 'V' shaped valley: produced in upper course because the river cuts down more quickly than the surrounding slopes are eroded.

27 6. Meander: the river starts to erode from side to side.7. River cliff: the river moves faster on the outside of the bend and cuts into the valley side. The erosion undercuts the ground causing it to collapse, leaving a cliff.8. River beach (Slip-off slope): the river moves more slowly on the inside of the bend. It cannot carry the larger pebbles and these are dropped here.

29 9. Ox-bow lake: during floods the river cuts through the neck of a large meander. The outside bend is left as a shallow lake.10. Flood plain: the river is flowing in a very wide, flat valley. When it floods, it spreads over the flood plain.11. Levée: during floods the overflowing river is slowed as it leaves its bed. Silt is deposited along the banks first. Over the years the deposits build up into high ridges.12. Estuary: the open mouth of the river, where it meets the sea.

30 River channelA river is fresh water flowing across the surface of the land, usually to the sea. It flows in a channel. The bottom of the channel is called the bed and the sides of the channel are called the banks.

33 River terms Source - The source is the beginning of a stream or river.Mouth - The mouth is the end of a river, where it empties into a large body of water.Tributary - A tributary is a river or stream that flows into another stream, river, or lake.Confluence – to the point where a tributary joins a larger river.Drainage basin – the area drained by a river and its tributaries.Watershed – the boundary of the drainage basin which is usually a ridge of high land.

35 Give the meanings of these wordsSOURCEWATERSHEDTRIBUTARYCONFLUENCEMOUTHRIVER CHANNELDRAINAGE BASINDELTA

36 AnswersSOURCEThe place where a river starts, usually in high ground. Can be in the form of a spring, lake or glacier.WATERSHEDThe area of highland which forms the edge of a drainage basin.TRIBUTARYA small stream which flows into a larger one, adding water to it and making it bigger.DRAINAGE BASINAn area of land drained by a river and its tributaries.MOUTHThe end of a river's course, where it flows into the sea or a lake.CHANNELThe space between the banks of a river where it flows.CONFLUENCEThe point where a small stream flows into the main channel, or where 2 small streams join.DELTAA landform where the mouth of a river flows into an ocean, sea, desert, estuary, lake or another river.

37 Fill in the spaces putting in the missing terms and the missing definitionsThe place where a river starts, usually in high ground. Can be in the form of a spring, lake or glacier.WATERSHEDTRIBUTARYAn area of land drained by a river and its tributaries.MOUTHCHANNELThe point where a small stream flows into the main channel, or where 2 small streams join.DELTA

38 Shaping the landThe river works to shape the land. It does it in 3 ways:Erosion – wears away the landTransportation – moves the material from one place to anotherDeposition – drops the material and builds new landforms

39 What is erosion?Erosion is the wearing away of the land (like sandpaper)Weathering breaks up and weakens the surface of the rocks while erosion wears away and removes the loosened material

43 Processes of ErosionErosion involves the wearing away of rock and soil found along the river bed and banks. Erosion also involves the breaking down of the rock particles being carried downstream by the river.There are four main forms of river erosion:Hydraulic action - river wears away the river bank from underneath (force of the water against river banks)Attrition - rocks being carried by the river smash together and break into smaller particles.Abrasion - rocks carried along by the river wear down the river bed and banksSolution - smaller particles are dissolved into the river.

46 TransportRivers pick up and carry material as they flow downstream. A river may transport material in four different ways:Solution - minerals are dissolved in the water and carried along in solution.Suspension - fine light material is carried along in the water.Saltation - small pebbles and stones are bounced along the river bed.Traction - large boulders and rocks are rolled along the river bed.

47 Rivers need energy to transport material, and levels of energy change as the river moves from source to mouth.When energy levels are very high, large rocks and boulders can be transported. Energy levels are usually higher near a river's source, when its course is steep and its valley narrow. Energy levels rise even higher in times of flood.When energy levels are low, only small particles can be transported (if any). Energy levels are lowest when velocity drops as a river enters a lake or sea (at the mouth).

48 DepositionWhen a river loses energy, it will drop or deposit some of the material it is carrying.Deposition may take place when a river enters shallow water or when the amount of water decreases - for example, after a flood or during times of drought.Deposition is common towards the end of a river's journey, at the mouth.Deposition at the mouth of a river can form deltas - for example, the Mississippi Delta

49 The rivers course Small pebbles in river.River at its widest and deepest.Large rocks in the river.River getting wider and deeperLarge boulders in the river.River narrow and shallow

50 3 stages of the riverThe journey of river from source (where the river begins) to mouth (where the river ends) is sometimes called the course of the river. The course of a river can be divided into three main sections:upper coursemiddle courselower course

51 Rivers always flow downwards from highland areas to lowland areas, through the upper, middle, and finally the lower course.

56 ErosionErosion involves the wearing away of rock and soil found along the river bed and banks. Erosion also involves the breaking down of the rock particles being carried downstream by the river.There are four main forms of river erosion:Hydraulic action - river wears away the river bank from underneathAttrition - rocks being carried by the river smash together and break into smaller particlesAbrasion - rocks carried along by the river wear down the river bed and banksSolution - smaller particles are dissolved into the river